This invention relates to efficient methods of recording an audio signal in a semiconductor memory and reproducing the recorded signal.
Semiconductor memories are used for recording and reproducing messages and other types of audio signals in many products and systems, including telephone sets, toys, and public address apparatus. Compared with magnetic tape recording, since it has no moving parts, semiconductor memory offers the advantages of small size, low power, long life, and high reliability, but a semiconductor memory has a limited data capacity. With conventional recording methods there is a fixed maximum limit, often measured only in seconds, on the length of the recording. If an attempt is made to record beyond this limit, part of the recording is inevitably lost.
One reason for these problems is that conventional systems lack a method of overwriting existing data without completely losing portions of the already-recorded signal.